April 2009 - Posts

Recursive SQL queries are built with recursive common table expressions (CTEs). You can look at the execution semantics of a recursive CTE from two different, but equivalent, perspectives. We can call the first one the UNION ALL view. The following pseudo Read More...

“My database is in the simple recovery mode. No, I don’t have any large, long-running, or replication transactions, and yes, I have enough number of VLFs to go around, about 250 of them to be precise. Why does my transaction log keep autogrowing?” As Read More...

In a multi-process/multi-thread system, locking is central to maintain data consistency and keep things in order. It is inevitably at the root of almost all the concurrency and scalability problems. To understand the behavior of such a system and to troubleshoot Read More...